This invention relates generally to shelters and protectors which are placed around young trees or other plants for the purposes of accelerating growth and preventing damage.
Young trees, grapevines and other plants can be vulnerable to damage from small animals. To help prevent such damage, plant protectors have been wrapped around the base or trunk of the tree or other plant during its early growth. An example of such a protector is a cylindrical plastic tube which is placed around young trees, vines and other types of plants. These protectors can also act as mini-greenhouses to accelerate growth of the young plants. Placing a properly sized and colored tube around a young plant or tree has been shown to enhance plant growth. In the forestry industry, the tubes are used to accelerate growth and promote straight tree trunks. In the viticulture industry, the tubes are used to accelerate plant growth and reduce the time required before the first harvest. Studies have shown that appropriate shape, height, diameter, color, and venting of such tubes can all contribute to enhancing plant growth. Recently, studies have shown that grape vines benefit from the tube well after the vine is tied to the trellis. This discovery has promoted the design of grow tubes that can be removable. In hot climates, studies have concluded that venting of the grow tube by providing holes at selected positions in the tube can help reduce leaf-burn and promote a healthier plant. The disadvantage to such venting is that the vent holes allow herbicides to enter (and possibly damage) the root area.
As the tree or plant matures, the tube protectors may begin to engage the plant and inhibit growth. To remove the tube from around the tree or plant, the tube must be pulled off of the plant or the tube must be cut away, either of which might result in damage to the tree or plant. Cutting the tube usually prevents reuse of the tube on another plant.
Various plant or tree protectors have been developed in an attempt to protect young trees and plants from damage without the limitation of having to cut away the protector when the tree or plant has matured. One fairly common example of such a plant protector is a plastic sheet which is wrapped around the trunk of a tree, with its two ends joined by a coupling mechanism. The traditional coupling mechanism does not allow for the partial opening of the tree protector. A further disadvantage is that extended use can lead to the deformation of the tree protector. The tree protector may be positioned around the trunk of a tree for a relatively long period of time, sometimes several years, during which time it can tend to conform to the shape of the tree and may sag or otherwise lose its proper shape.
A wide variety of other types of tree protectors have been developed. These too have typically been difficult to remove and replace, and often have been too complex and expensive to be practical.
A plant protector for providing growth enhancement and protection against damage in accordance with the present invention includes first and second shells, each formed of a rigid plastic material having a semi-cylindrical shaped portion. The shells have flanges at the edges of the semi-cylindrical portions that run longitudinally. Each shell preferably also includes raised ribs running circumferentially in the semi-cylindrical portions, perpendicular to the flanges, and regularly spaced apart so as to provide strength and rigidity to the shells. The ribs face outwardly when the shells come together, and the flanges can be joined such that the shells form a cylindrical tube when engaged together. The shells may be conveniently locked together in place around a tree or other plant by a locking means on the flanges for locking the first shell to the second shell.
The plant protector may be placed around a tree or other plant without the concern that it will inhibit growth as the tree or plant matures because the protector can be easily removed by disengaging the locking means when it is appropriate to do so. Further, the locking means can comprise closures formed as snap-fit interlocking parts on the flanges that can be pulled apart by the growing tree, thereby limiting the pressure that can be applied by the plant protector to the growing tree.
The plant protector may be partially opened in order to expose part of the tree or plant for purposes of maintenance, repair, or diagnostics, and then reclosed. Some or all of the closures along the length of the protector may be disengaged, as the user may so desire.
The plant protector is preferably made of a rigid plastic material in order to resist attack by animals and to withstand an external impact (e.g., from a lawnmower). Due to the rigid structure and the two shell construction of the tree protector, when the tree protector is removed from around a tree, it retains its original shape and physical integrity, and may be applied to another tree or plant or disposed of.
The first and second shells are conveniently and preferably made by a vacuum forming process, using molds having the shape of each shell. As is conventional in vacuum forming, a flat sheet of plastic is heated to a softening temperature, and the softened plastic is drawn under vacuum into the mold, where the plastic cools and hardens into the shape defined by the mold.
The upper and lower edge sections of the semi-cylindrical portions preferably flare outwardly so as to allow room for root expansion at the lower edge, and branch expansion at the upper edge, and to minimize the chance that the top and bottom edges of the protector will chaff against the trunk.
The first and second shells are preferably connected by a locking means on the flanges of each of the shells. The use of a locking means on both edges of the shells is not required, however. The first and second shells may be engaged by a locking means at one edge of each of the first and second shells, and with the first and second shells having flanges terminating at a hinge (e.g., an integral xe2x80x9cliving hingexe2x80x9d) at the other edge of each shell which joins the two shells. The locking means is preferably also a vacuum formed structure formed integrally on the flanges of the first and the second shells. The locking means may comprise several mating bosses and indentations formed on the flanges on opposite sides of the first and second shells and positioned periodically along the longitudinal edge of each flange. Alternatively, the locking means may comprise a longitudinally extending groove and a longitudinally extending ridge formed on the flanges on opposite sides of the first and second shells for locking the shells when the shells are engaged together. The locking means may also take the form of an overlapping lip on one of the flanges of the first shell that envelopes an edge of one of the flanges on the second shell such that the lip and the edge lock together, whereby a cylindrical tube is formed when the first shell and the second shell are engaged together.
The plant protector may also have one or more grooves formed on the semi-cylindrical portions for receiving a security stake for stabilizing the plant protector in the ground and one or more apertures at the top of the each flange for passing through a piece of rope to tie the shell portions together or to a stake.
The flanges on the two shells may be scalloped wherein an outwardmost part of one flange meets an inwardmost part of the abutting flange so that the flanges can be easily gripped to draw the shells apart or bring the flanges together.
Further, the plant protector of the invention may include at least one and preferably several tortuous path vent tubes that extend from the edges of the flanges to communication with the interior of the protector. The vent tubes may conveniently be formed as semi-cylindrical raised portions in the flat flanges, with the indentations in abutting flanges matching with each other to form a complete vent tube. The vent tubes preferably have an upwardly (or vertically) extending section in addition to (radially) inwardly extending sections. The vertical section helps to minimize the migration of liquid herbicides through the vent tubes into the interior of the protector.
Further objects, features and advantages of the invention will be apparent from the following detailed description when taken in conjunction with the accompanying drawings.